Tightening device

Abstract

A device for tightening a plurality of threaded members at the same time with proper torque without necessitating a cumbersome procedure of rotating the members one by one through a specified small angle at a time and without unequivalent tightening of the members, the tightening device (1) comprises two rotary shafts (6) each provided at a forward end thereof with a wrench portion (8) fittable to the threaded member (44), motors (3) for individually driving the rotary shafts (6) and a control unit (9) for detecting the tightening torque of each threaded member (44) and controlling the motor (3) based on the detected value to ensure proper tightening, the control unit (9) checking the tightening torque of each threaded member (44) as to whether the torque is within a predetermined range and whether the difference in tightening torque between the threaded members (44) is within a predetermined range.

What is claimed is: 
     
       1. A tightening device for tightening up a plurality of threaded members at the same time, the tightening device comprising plurality of rotary shafts each provided at a forward end thereof with a wrench portion fittable to one of a plurality of threaded members, drive means for individually driving the rotary shaft, and control means for detecting the amount of tightening of each threaded member and the tightening torque thereof and controlling the drive means based on the value detected, the control means comprising drive stop means for discontinuing the drive upon the amount of tightening of each threaded member reaching a specified value based on the time when the tightening torque reaches a predetermined value, and judging means for judging each threaded member to be properly tightened in the case where the tightening torque of the threaded member is within a predetermined range, with the difference in tightening torque between the threaded members within a predetermined range, when the drive is discontinued, said drive means comprising motors for driving the respective rotary shafts, each of said motors having a spur gear attached to a forward end of a drive shaft thereof, and each of the rotary shafts having a pinion attached to a base end thereof and meshed with said spur gear. 
     
     
       2. A tightening device as defined in claim 1 characterized in that said spur gear is attached to the forward end of the motor drive shaft by a joint, with play between the joint and the motor drive shaft for permitting the spur gear to rotate slightly about an axis of the motor shaft relative to said shaft. 
     
     
       3. A tightening device for tightening up a plurality of threaded members at the same time, the tightening device comprising plurality of rotary shafts each provided at a forward end thereof with a wrench portion fittable to one of a plurality of threaded members, drive means for individually driving the rotary shaft, and control means for detecting the amount of tightening of each threaded member and the tightening torque thereof and controlling the drive means based on the value detected, the control means comprising drive stop means for discontinuing the drive upon the amount of tightening of each threaded member reaching a specified value based on the time when the tightening torque reaches a predetermined value, and judging means for judging each threaded member to be properly tightened in the case where the tightening torque of the threaded member is within a predetermined range, with the difference in tightening torque between the threaded members within a predetermined range, when the drive is discontinued, characterized in that said wrench portion is connected to the rotary shaft movably axially thereof. 
     
     
       4. A tightening device as defined in claim 2 characterized in that a coiled compression spring is provided for biasing said wrench portion so as to move said wrench portion forward relative to said rotary shaft. 
     
     
       5. A tightening device for tightening up a plurality of threaded members at the same time, the tightening device comprising a plurality of rotary shafts each provided at a forward end thereof with a wrench portion fittable to one of the plurality of threaded members, drive means for individually driving the rotary shafts, and control means for detecting the amount of tightening of each threaded member and the tightening torque thereof and controlling the drive means based on the values detected, the control means comprising drive stop means for discontinuing the drive upon the tightening torque of each threaded member reaching a predetermined value with the tightening amount within a specified range, and judging means for judging each threaded member to be properly tightened in the case where the difference in tightening torque between the threaded members is within a predetermined range when the drive is discontinued, said drive means comprising motors for driving the respective rotary shafts, each of the motors having a spur gear attached to a forward end of a drive shaft thereof, and each of the rotary shafts having a pinion attached to a base end thereof and meshing with the spur gear. 
     
     
       6. A tightening device as defined in claim 5, characterized in that said spur gear is attached to the forward end of the motordrive shaft by a joint, with play provided between the joint and the motor drive shaft for permitting the spur gear to rotate slightly about an axis of the motor shaft relative to said shaft. 
     
     
       7. A tightening device for tightening up a plurality of threaded members at the same time, the tightening device comprising a plurality of rotary shafts each provided at a forward end thereof with a wrench portion fittable to one of the plurality of threaded members, drive means for individually driving the rotary shafts, and control means for detecting the amount of tightening of each threaded member and the tightening torque thereof and controlling the drive means based on the values detected, the control means comprising drive stop means for discontinuing the drive upon the tightening torque of each threaded member reaching a predetermined value with the tightening amount within a specified range, and judging means for judging each threaded member to be properly tightened in the case where the difference in tightening torque between the threaded members is within a predetermined range when the drive is discontinued, characterized in that said wrench portion is connected to the rotary shaft movably axially thereof. 
     
     
       8. A tightening device as defined in claim 7, characterized in that a coiled compression spring is provided for biasing the wrench portion so as to move the wrench portion forward relative to the rotary shaft. 
     
     
       9. A tightening device for tightening up a plurality of threaded members at the same time, the tightening device comprising a plurality of rotary shafts each provided at a forward end thereof with a wrench portion fittable to one of the plurality of threaded members, drive means for individually driving the rotary shafts, and control means for detecting the amount of tightening of each threaded member and the tightening torque thereof and controlling the drive means based on the values detected, the control means comprising drive stop means for discontinuing the drive upon the tightening torque of each threaded member reaching a predetermined value with the tightening amount within a specified range, and judging means for judging each threaded member to be properly tightened in the case where the difference in tightening torque between the threaded members is within a predetermined range when the drive is discontinued, wherein the control means further comprises excessive torque abnormality indicating means for discontinuing tightening and indicating abnormal tightening upon the tightening torque of one of the threaded members exceeding the predetermined value before the amount of tightening of the threaded member reaches a specified lower limit, said drive means comprising motors for driving the respective rotary shafts, each of the motors having a spur gear attached to a forward end of a drive shaft thereof, and each of the rotary shafts having a pinion attached to a base end thereof and meshed with the spur gear. 
     
     
       10. A tightening device as defined in claim 9, characterized in that said spur gear is attached to the forward end of the motor drive shaft by a joint with play provided between the joint and the motor drive shaft for permitting the spur gear to rotate slightly about an axis of the motor shaft relative to the shaft. 
     
     
       11. A tightening device for tightening up a plurality of threaded members at the same time, the tightening device comprising a plurality of rotary shafts each provided at a forward end thereof with a wrench portion fittable to one of the plurality of threaded members, drive means for individually driving the rotary shafts, and control means for detecting the amount of tightening of each threaded member and the tightening torque thereof and controlling the drive means based on the values detected, the control means comprising drive stop means for discontinuing the drive upon the tightening torque of each threaded member reaching a predetermined value with the tightening amount within a specified range, and judging means for judging each threaded member to be properly tightened in the case where the difference in tightening torque between the threaded members is within a predetermined range when the drive is discontinued, wherein the control means further comprises excessive torque abnormality indicting means for discontinuing tightening and indicating abnormal tightening upon the tightening torque of one of the threaded members exceeding the predetermined value before the amount of tightening of the threaded member reaches a specified lower limit, and said wrench portion is connected to the rotary shaft movably axially thereof. 
     
     
       12. A tightening device as defined in claim 11, characterized in that a coiled compression spring is provided for biasing the wrench portion so as to move the wrench portion forward relative to the rotary shaft. 
     
     
       13. A tightening device for tightening up a plurality of threaded members at the same time, the tightening device comprising a plurality of rotary shafts each provided at a forward end thereof with a wrench portion fittable to one of the plurality of threaded members, drive means for individually driving the rotary shafts, and control means for detecting the amount of tightening of each threaded member and the tightening torque thereof and controlling the drive means based on the values detected, the control means comprising drive stop means for discontinuing the drive upon the tightening torque of each threaded member reaching a predetermined value with the tightening amount within the specified range, and judging means for judging each threaded member to be properly tightened in the case where the difference in tightening torque between the threaded members is within a predetermined range when the drive is discontinued, said control means further comprising excessive torque abnormality indicating means for discontinuing tightening and indicating abnormal tightening upon the tightening torque of one of the threaded members exceeding the predetermined value before the amount of tightening of the threaded member reaches a specified lower limit, said control means further comprising deficient torque abnormality indicating means for discontinuing tightening and indicated abnormality tightening when the tightening torque of one of the threaded members is below the predetermined value even if the amount of tightening of the threaded member reaches a specified upper limit, the drive means comprising motors for driving the respective rotary shafts, each of the motors having a spur gear attached to a forward end of a drive shaft thereof, and each of the rotary shafts having a pinion attached to a base end thereof and meshing with the spur gear. 
     
     
       14. A tightening device as defined in claim 13, wherein each of the motors has a spur gear attached to a forward end of a drive shaft thereof, and comprises main tightening means for finally tightening up each threaded member to the proper value when the threaded member is judged to be properly tightened, further characterized in that the spur gear is attached to the forward end of the motor drive shaft by a joint, with play provided between the joint and the motor drive shaft for permitting the spur gear to rotate slightly about an axis of the motor shaft relative to the shaft. 
     
     
       15. A tightening device for tightening up a plurality of threaded members at the same time, the tightening device comprising a plurality of rotary shafts each provided at a forward end thereof with a wrench portion fittable to one of the plurality of threaded members, drive means for individually driving the rotary shafts, and control means for detecting the amount of tightening of each threaded member and the tightening torque thereof and controlling the drive means based on the values detected, the control means comprising drive stop means for discontinuing the drive upon the tightening torque of each threaded member reaching a predetermined value with the tightening amount within the specified range, and judging means for judging each threaded member to be properly tightened in the case where the difference in tightening torque between the threaded members is within a predetermined range when the drive is discontinued, said control means further comprising excessive torque abnormality indicating means for discontinuing tightening and indicating abnormal tightening upon the tightening torque of one of the threaded members exceeding the predetermined value before the amount of tightening of the threaded member reaches a specified lower limit, said control means further comprising deficient torque abnormality indicating means for discontinuing tightening and indicated abnormality tightening when the tightening torque of one of the threaded members is below the predetermined value even if the amount of tightening of the threaded member reaches a specified upper limit, with said wrench portion being connected to the rotary shaft movably axially thereof. 
     
     
       16. A tightening device as defined in claim 15, characterized in that a coiled compression spring is provided for biasing the wrench portion so as to move the wrench portion forward relative to the rotary shaft. 
     
     
       17. A tightening device for tightening up a plurality of threaded members at the same time, the tightening device comprising plurality of rotary shafts each provided at a forward end thereof with a wrench portion fittable to one of a plurality of threaded members, drive means for individually driving the rotary shaft, and control means for detecting the amount of tightening of each threaded member and the tightening torque thereof and controlling the drive means based on the value detected, the control means comprising drive stop means for discontinuing the drive upon the amount of tightening of each threaded member reaching a specified value based on the time when the tightening torque reaches a predetermined value, and judging means for judging each threaded member to be properly tightened in the case where the tightening torque of the threaded member is within a predetermined range, with the difference in tightening torque between the threaded members within a predetermined range, when the drive is discontinued, wherein the specified value for the amount of tightening is smaller than a pre-set value for the final amount of tightening, and the control means further comprises main tightening means for tightening up each threaded member until the proper final torque value is reached when the threaded member is judged to be properly tightened, said drive means comprises motors for driving the respective rotary shafts, each of said motors having a spur gear attached to a forward end of a drive shaft thereof, and each of the rotary shafts having a pinion attached to a base end thereof and meshed with said spur gear. 
     
     
       18. A tightening device as defined in claim 17, characterized in that the spur gear is attached to the forward end of the motor drive shaft by a joint, with play provided between the joint and the motor drive shaft for permitting the spur gear to rotate slightly about an axis of the motor drive shaft relative to the shaft. 
     
     
       19. A tightening device for tightening up a plurality of threaded members at the same time, the tightening device comprising plurality of rotary shafts each provided at a forward end thereof with a wrench portion fittable to one of a plurality of threaded members, drive means for individually driving the rotary shaft, and control means for detecting the amount of tightening of each threaded member and the tightening torque thereof and controlling the drive means based on the value detected, the control means comprising drive stop means for discontinuing the drive upon the amount of tightening of each threaded member reaching a specified value based on the time when the tightening torque reaches a predetermined value, and judging means for judging each threaded member to be properly tightened in the case where the tightening torque of the threaded member is within a predetermined range, with the difference in tightening torque between the threaded members within a predetermined range, when the drive is discontinued, wherein the specified value for the amount of tightening is smaller than a pre-set value for the final amount of tightening, and the controls means further comprises main tightening means for finally tightening up each threaded member to the proper value when the threaded member is judged to be properly tightened, and said wrench portion is connected to the rotary shaft movable axially thereof. 
     
     
       20. A tightening device as defined in claim 19, characterized in that a coiled compression spring is provided for biasing said wrench portion so as to move the wrench portion forward relative to the rotary shaft. 
     
     
       21. A tightening device for tightening up a plurality of threaded members at the same time, the tightening device comprising a plurality of rotary shafts each provided at a forward end thereof with a wrench portion fittable to one of the plurality of threaded members, drive means for individually driving the rotary shafts, and control means for detecting the amount of tightening of each threaded member and the tightening torque thereof and controlling the drive means based on the values detected, the control means comprising drive stop means for discontinuing the drive upon the tightening torque of each threaded member reaching a predetermined value with the tightening amount within a specified range, and judging means for judging each threaded member to be properly tightened in the case where the difference in tightening torque between the threaded members is within a predetermined range when the drive is discontinued, wherein the predetermined value for the tightening torque is smaller than a pre-set value for final tightening torque, and the control means further comprises main tightening means for tightening up each threaded member until the proper final torque value is reached when the threaded member is judged to be properly tightened, the device means comprising motors for driving the respective rotary shafts, each of the motors having a spur gear attached to a forward end of a drive shaft thereof, and each of the rotary shafts having a pinion attached to a base end thereof and meshing with the spur gear. 
     
     
       22. A tightening device as defined in claim 21, characterized in that the spur gear is attached to the forward end of the motor drive shaft by a joint, with play provided between the joint and the motor drive shaft for permitting the spur gear to rotate slightly about an axis of the motor shaft relative to the shaft. 
     
     
       23. A tightening device for tightening up a plurality of threaded members at the same time, the tightening device comprising a plurality of rotary shafts each provided at a forward end thereof with a wrench portion fittable to one of the plurality of threaded members, drive means for individually driving the rotary shafts, and control means for detecting the amount of tightening of each threaded member and the tightening torque thereof and controlling the drive means based on the values detected, the control means comprising drive stop means for discontinuing the drive upon the tightening torque of each threaded member reaching a predetermined value with the tightening amount within a specified range, and judging means for judging each threaded member to be properly tightened in the case where the difference in tightening torque between the threaded members is within a predetermined range when the drive is discontinued, wherein the predetermined value for the tightening torque is smaller than a pre-set value for final tightening torque, and the control means further comprises main tightening means for tightening up each threaded member until the proper final torque value is reached when the threaded member is judged to be properly tightened, and wherein the wrench portion is connected to the rotary shaft movably axially thereof. 
     
     
       24. A tightening device as defined in claim 23, characterized in that a coiled compression spring is provided for biasing the wrench portion so as to move the wrench portion forward relative to the rotary shaft.